cold air feeds

[shepherd]

does anyone know how much ,if any bhp is gained from them and how much ?

and does a feed air feed affect anything else ?

cheers

[chimp007_uk]

minimal, but it depends what power you're running etc etc the idea is to get colder ait than the engine bay air to getting a better comustion. the colder the air, the more dense it is so you get more molecules in the same volume as hotter expanded air... its not hard to run some ducting, i always find that cold damp mornings are the best to notice the affects of cold air.

[chimp007_uk]

go what injection for the fun of it, thats my next attempt.

[andy_srt40]

cold air ducts aren't mush use on vx's unless you have ITB's or twin carbs, then they help to get cold air to the inlet round the back of the engine,

with vauxhalls the best thing you can do is do your best to get the warm air out, byt either raising the bonnet, putting holes in the bulk head or removing the bulkhead completely

i fitted a cold air feed on my t40'd gte nova and it made no difference, i then raised the bonnet and that made it a little better but the best thing i did was use a 2" inch hole saw on the bulkhead and that was only thing that made a noticable difference, if yoyu ahve a cone filter, then try heat sheilding it, or relocate the filter to under neath the scuttle panel ;)

[Jack]

lmfao water injection, thats a bit overkill. Only really useful on big power turbos tbh.

I've heard reports of raising the bonnet messing up underbonnet pressure and air flow and making engines run hotter :wtf:

[meritlover]

there is a rule of thumbs but i cant remember what it is. like 4% loss for every deg rise in air temp, or 1% loss for every 4 deg increased air temp. i forget. no doubts someone will abuse me because i read that from a book but i am not scared by these critisisms.

you might notice it and you might not, depending on how highly stringed your engine is. if the timing is on the verge of pinking or getting det, then a few deg of cold air may allow for a few more deg advance....but maybe not..

[Lee-170]

cold airfeeds only really work at about 60mph+ and they dnt really make a diffrence then IMO

[andy_srt40]

makes the engine run hotter? i can see no reason why that would be mate, as the air goes straight in and out again before it gets hot,

but like i said best way is removal of the bulk head, keeps the nice high pressure area at the back of the bonnet and stop your car looking like the bonnet's about to fly off lol

i suppose3 it could make it run hotter if the air doesn't make it round the engine coz its so easy for it to escape but novas have lots of gapes behind the bumper etc to aid airflow up and around the engine

[meritlover]

cold airfeeds only really work at about 60mph+ and they dnt really make a diffrence then IMO

why is this the case? are you not thinking about ram air feeds?

[meritlover]

lmfao water injection, thats a bit overkill. Only really useful on big power turbos tbh.

I've heard reports of raising the bonnet messing up underbonnet pressure and air flow and making engines run hotter :wtf:

water injection is well over the tops. i have heard also that this is the case that interfering/violating with the bonet scares the air to go out the top of the bonnet as apposed to under the car (and away from the inlet manifold)

[andy_srt40]

why is this the case? are you not thinking about ram air feeds?

ram air and cold air feeds are essentially the same thing, they both feed cold air to the air filter, as said until the airspeed can overcome the pressure in the engine bay they are of no use

[chimp007_uk]

water injection, isn;t too overkill. lowering cylinder temperatures increases the combustion force resulting in more power. therefore, on small ingines, it isnt as overkill as you think. and yeh, there is a rule of thumb for intake temp and power, but again its was a couple of years ago when i did it at uni.

[meritlover]

ram air and cold air feeds are essentially the same thing, they both feed cold air to the air filter, as said until the airspeed can overcome the pressure in the engine bay they are of no use

no, there is a difference. a cold feed is a hose that is directed around a filter. a ram-air kit is a contained/sealed airbox with a hose that is mounted at the front of the car or on a scoop.

[meritlover]

water injection, isn;t too overkill. lowering cylinder temperatures increases the combustion force resulting in more power. therefore, on small ingines, it isnt as overkill as you think. and yeh, there is a rule of thumb for intake temp and power, but again its was a couple of years ago when i did it at uni.

agreed there are gains to be had, but monies spent Vs performances gained + the added weights of carrying water all the way to Tescos means the money will be better spent else where.

[Philsutton]

water injection, isn;t too overkill. lowering cylinder temperatures increases the combustion force resulting in more power. therefore, on small ingines, it isnt as overkill as you think. and yeh, there is a rule of thumb for intake temp and power, but again its was a couple of years ago when i did it at uni.


tbh nitrous would be so much better at the job than water injection, its just people get very scared with it for some reason.

[meritlover]

tbh nitrous would be so much better at the job than water injection, its just people get very scared with it for some reason.

because most peoples that install it are idiots and much destroy/melt engines by being stupid and wrong. there are also a lot of very dangerousness installations in road cars.
nitros has the benefit of cooling the inlet charge in a much of the same way as a water injection does.

[chimp007_uk]

nitrogen oxide doesn't cool the inlet charge at all... n2o at temperature, splits into nitrogen and oxygen which is why you see massive powers gains you get a better combustion!
in theory its safer to run water injection. i dont mean water/ethanol, just water...

[meritlover]

yes...and 'splitting the NOS' takes energy...which comes from the heat of the inlet charge....which reduces the temperature.

cooler charge is a by product of adding nos. anything that evaporates will cause a temp drop. the NOS is liquid right up to the jet-then has to vapourise to form a gas. think about in terms of Joules thompson effect.

[Philsutton]

nitrogen oxide doesn't cool the inlet charge at all... n2o at temperature, splits into nitrogen and oxygen which is why you see massive powers gains you get a better combustion!
in theory its safer to run water injection. i dont mean water/ethanol, just water...


lol, you dont understand the basic physics behide it then. The Nitrous oxide does cool the intake by quite a lot.

[chimp007_uk]

i'm guessing its an endothermic reaction then?

[Jack]

in theory its safer to run water injection. i dont mean water/ethanol, just water...
Ethanol is never used in water injection as the ethanol is too corrosive! Methanol or isopropanol are used instead.

Reason I said its mainly used on turbos is they tend to run vastly hotter than n/a engines, even with large coolers.

[chimp007_uk]

sorry, i ment methanol...

[andy_srt40]

no, there is a difference. a cold feed is a hose that is directed around a filter. a ram-air kit is a contained/sealed airbox with a hose that is mounted at the front of the car or on a scoop.

ahh l'm with you now

when setup like that they work.

I thought were talking crappy aftermarket jobs where they have a flexible hose with a trumpet similar to a regular cold air feed that you can direct anywhere. and probably make it harder for the engine to breath lol lol

agreed. if directed into the bay that way you will get much more flow than one behind the grill like they are usually mounted. if you combined a feed like that with the outlet position low down in the bay and then raise the bonnet it could very possibly produce good results???

[Philsutton]

Putting aside the chemical reaction, gas flowing through a small hole at high speed (the nitrous is at about 900psi) gives you a cooling effect.

[meritlover]

i'm guessing its an endothermic reaction then?

no not really. more like Joules-Thompson effect

[shepherd]

so, would a cold air feed , a raised bonnet and "NOS" be a good combo?


and thank you all for all this great info :)

cheers

[meritlover]

some sort of 'collector' around the filters (made from aluminium/tin sheet), some ducting to the front or scoop 'like a subaru impreza' or a hose to the front will be ideal. dont play with NOS unless you know what your doing.
just get cold air to the carbs regardless how you do it really.